Convertible top lift actuator



July 6, 1954 J. PICKLES CONVERTIBLE TOP LIFT ACTUATOR 2 Sheets-Sheet 1Filed Feb. 11 1953 INVENTOR- E c'i/es, BY 4 fl7'7ZF/YEY5,

July 6, 1954 J. PICKLES CONVERTIBLE TOP LIFT ACTUATOR 2 Sheets-Sheet 2Filed Feb. 11 1953 INVENTOR. Jj/i 7 zci/es.

w TdFNEVi Patented July 6, 1954 CONVERTIBLE TOP LIFT ACTUATOR JosephPickles, Dearborn, Mich., assignor to Hupp Corporation, Cleveland, Ohio,a corporation of Virginia Application February 11, 1953, Serial No.336,241

This invention relates to toplift actuators, and more particularly toelectric motor driven screw type actuators for lifting and loweringconvertible tops of automotive vehicles and for similar purposes.

It is an object of the present invention to provide an improved topliftactuator utilizing a pair of extensible elements which may beindependently driven by two constant speed motors, and in which theamount of friction in the operating parts of the actuator issubstantially minimized, whereby the actuators may be driven in reverseby hand operation of the toplift.

It, is another object to provide an improved toplift actuator of theabove nature, in which a ball nut construction is utilized, therebyachieving a reversible construction which may be operated in eitherdirection.

It is a further object to provide an improved toplift actuatingmechanism of the screw type as above described, in which novelfreewheeling means are provided for preventing undue strain in theheader of the windshield when the top is lifted, and forpermitting theelectric motors to be energized in a stall position of the actuatorwithout harm.

Other objects, features, and advantages of the present invention willbecome apparent from the subsequent description, taken in conjunctionwith the accompanying drawings.

In the drawings:

Fig-ure 1. is a side cross-sectional view of a novel toplift actuatoraccording to the invention, showing the freewheeling construction;

Figure 2 is an end elevational view showing the motor mounting means;

- Figure 3 is a cross-sectional detail view of the drive means betweenthe motor shaft and the screw shaft, taken along the line 3-3 of Figure1;

Figure 4 is an electrical circuit diagram showing the wiringfor a pairof driving motors of the full field reversing type; and

Figure 5 is an electrical circuit diagram showing the wiring arrangementfor a pair of driving motors of the split field reversing type.

The toplift actuator comprises a housing generally indicated at H whichis pivotally secured at its lower end to a standard 12 forming part ofthe motor vehicle chassis, and is connected at its upper end to a memberl3 forming part of a conventiona1 linkage (not shown) for a vehicleconvertible top. It will be understood that while only a single actuatoris shown in the illustrated embodiment, a pair of identical'actuators,one

11 Claims. (Cl. 74-4243) 2 on each side of the vehicle, will normally beused to actuate both sides of the toplift linkage if the actuator isused for this purpose. The housing I l is provided with clevis I4carrying a pivot pin I5 which connects the housing to standard l2, andin the illustrated embodiment the housing I I also carries an electricmotor 16, the end portion I! of the motor housing being formed as partof housing II. It will be understood however that the motor 16 could besupported in other ways within the scope of the invention.

The shaft [8 of motor l6 drives a worm IS, the shaft and worm beingsupported by a bearing 2i disposed within the housingand a thrustbearing 22 at the outer end of the worm and held by a plug 23. A seal 24is preferably provided at an intermediate portion of shaft l8 adjacentbearing 2|. The axis of shaft l8 and worm I9 is transverse to the axisof driving screw 25 of the actuator, which has a lower journal portion26 supported by an antifriction bearin 21 held by housing 1 I. Fixed bya pin 28 to extension 26 of the screw is a worm wheel 29 which is inmeshing engagement with worm l9. Extension 26 projects beyond worm gear29 as shown at 3| and is guided by a lower housing portion 32 having asealing cover 33. Bearing 2l is retained in the housing by means of aring 34, and a steel washer 35 is fixed to screw shaft extension 26.immediately above bearing 21, for reasons described below.

Screw shaft 25 extends upwardly from housing II and is provided with athread for receiving a plurality of spherical members which areconnected to ball nut 36, the ball nut being shown in its lower orretracted position in Figure 1. A dust cover 3! is preferably providedfor the screw shaft and ball nut, this cover being of tubular shape andsecured by band 38 at its lower end to i the housing. The ball nut isconnected to the linl; I3 of the toplift actuating linkage by means of atubular thrust member 39, which is rotatably secured to a tubularextension 4| of the ball nut. The internal diameter of guide extension4| is substantially the same as the internal diameter of the mainportion of thrust tube 39, and a shoulder 42 is formed at the junctureof the guide extension 4| with the main portion of the ball nut.

. The rotatable securing means for the thrust tube 39 is shown inFigure 1. The tube receives at its lower end a key comprising an annularmember 43, which fits in corresponding recesses in the thrust tube 39and ball nut 36. For example, member 43 may be formed of powderedmaterial for lubrication purposes, as two halves of a ring, the end 44of thrust tube 39 being spun over the key member after they are inplace. It will be understood that other forms of rotatably keying thethrust tube 39 to ball nut 36 could be used within the scope of theinvention. However, in any case the inherent frictional resistancebetween the thrust tube 39 and ball nut 36 due to the key 42 and guideextension 4| is substantially greater than the friction between the ballnut and screw shaft 25, so that rotation of the screw shaft willnormally drive the ball nut longitudinally of its axis.

The upper end of thrust tube 39 is provided with adjustable securingmeans for link [3, and in the illustrated embodiment this means includesan adapter member 45 having a threaded portion 46 secured within aninternally threaded portion 41 at the end of thrust tube 59. A lock nut48 is provided on adapter 45 for locking the adapter in the desiredlongitudinal position with respect to thrust tube 39. The upper end 49of adapter 45 is bifurcated and carries a pivot pin for connection withlink IS. The upper end of dust cover 31 may be provided with an inturnedlip 52 surrounding thrust tube 39 as shown in Figure 1.

Means are provided for rotating ball nut 36 along with the screw shaftwhen the ball nut has reached either end of its stroke, in order toprovide freewheeling of the actuator in either direction. This meanscomprises in the illustrated embodiment a stop member 53 secured by apin 54 to an extension 55 at the outer end of screw shaft 25. Stopmember 53 may be made of a plastic or other suitable material, and thediameter of the stop member is substantially the same as the internaldiameter of thrust tube 39. Since stop member 53 is held to the screwshaft 25, it will be seen that when the ball nut 36 reaches the outerend of the screw shaft, shoulder 42 will engage stop member 53. When theball nut reaches the inner end of the screw shaft the shoulder 56thereof will engage washer 35 which is fixed to the screw shaft. Ineither position, therefore, the resulting frictional contact between theball nut and stop member 53 or stop member 35 will cause ball nut 35 torotate with screw shaft 25. The thrust tube 39 being held againstrotation by its connection with link I3, the ball nut will rotaterelative to the thrust tube at key 43. Thus, the force produced on awindshield header when the top is lifted and strikes the header will besubstantially reduced, since the force exerted by the driving motor onthe linkage when the latter is stalled will be minimized.

The provision of a ball nut arrangement for the screw actuator willresult in the minimization of friction, thereby permitting an operatorto drive the actuator in either direction b hand, using the topliftlinkage. This reversal of operation is also facilitated by the helixangle of worm i9 and worm wheel 29, which is sufficient to allowreversibility of operation, and by the provision of anti-friction thrustbearing 22 for the worm I9. The advantages of this reversibility arereadily apparent, since the operator of the vehicle may lift or lowerthe top by hand in case of power failure.

Figures 4 and 5 illustrate two arrangements for simultaneously driving apair of electric motors to which the actuators are connected.Preferably, the motors are of a constant speed type, shunt wound motorsbeing illustrated. Due to the fact that the motors are of a constantspeed type and are simultaneously energized, mechanical synchronizationof the actuators is not essential, although such synchronization may beprovided if desired. Figure 4 illustrates schematically the wiringconnections for a pair of shunt wound shunt full field reversing motors51. A relay 58 connects the field and armature leads of the motors to abattery 59 or other source of power and a manual switch 6| shown as asingle pole double throw switch. As illustrated, the relay 58 comprisesa pair of relay coils 62 and 63 which are connected by leads 64 and 65respectively to the terminals 66 and 61 of switch 6 l pole terminal 68being connected to ground. The opposite ends of coils B2 and 63 areinterconnected by a lead 59 which in turn is connected by lead H to thepositive side of the battery 59, terminals 66 and 61 thus being at alltimes connected to the positive side of the battery.

One side of field 12 of each motor 51 is connected by a lead 13 tomovable contacts 14, 15 and 16 of relay 62, and the other end of eachfield winding 72 is connected by a lead 11 to movable contacts l8, l9and 8| of relay 63. When neither relay is energized, the relays are intheir leftward position as shown in Figure 4 in which contact 76 ofrelay 62 and contact 8| of relay 63 engage stationary contacts 82 and 83respectively, which are connected to the positive side of the battery.In this position therefore the fields 12 are not energized. One side ofarmature 84 of each motor 51 is connected by a lead 85 to the positiveside of the battery, and the other side of each armature is connected tostationary contacts 86 and 81, which are opposite contacts 15 and 1!!respectively.

In operation, the armature circuits of motors 51 will normally bedisconnected since contacts 75 and T9 are disengaged from contacts 86and 81 respectively, and since the shunt field windings 12 are notprovided with complete circuits. Upon closing of the terminal 55 of themanual switch 6! relay 62 will be energized and will move to the right.Contact 14 will engage a contact 88 connected to ground, and contact 15will engage contact 86. It will therefore be seen that one side ofarmature 84 of each motor will be grounded while the other side remainsconnected to the battery by lead 85. One side of each field winding 12will be connected to ground through lead 13, the other side remainingconnected to the battery 59 through lead 11, since contacts 8| and 83remain engaged. The driving motors will therefore rotate so as to movethe toplift actuators in one direction.

When it is desired to move the actuators in the opposite direction,terminal 61 of switch BI is engaged, thereby de-energizing relay 62 andenergizing relay 63. Contact I8 of relay 63 will engage a contact 89connected to ground, while contacts 18 and 87 are engaged. Contacts 16and 82 of relay 62 will also be engaged due to the leftward movement ofthis de-energized relay. Thus, armatures 84 will be energized in thesame direction as previously, but the polarity of field windings 12 willbe reversed, since lead 13 will be connected to the battery and lead 11to ground. The motors will therefore operate in the reverse direction.

Figure 5 illustrates an arrangement for operating a pair of split fieldreversing motors 9|.

The arrangement includes a single pole double throw switch 92 similar tothe previous embodiment, the pole terminal 93thereof being grounded andterminals 94 and 95 being connected to split fields 96 and 9'!respectively of each motor.

The other ends of-split fields 96 and 9! in each motor areinterconnected by a lead 98, this lead beingconnected to one side ofarelay coil 99 by lead Il. These relay coils are preferably heavy lowresistance coils capable of carrying relatively large amperage withsmall voltage drop, and the other ends of the coils are interconnectedby a lead I02 which is connected to the positive side of battery I03.Contact arm I04 of each relay is in series with the armature circuit I05of its corresponding motor, the other side vI06 of each armature circuitbeing grounded.

In operation, with switch 92 open the field coil 96 and 91V will bede-energized and relays 99 will likewise be de-energized, with armatureswitches I04 open. If terminal 94 of switch 92 is closed, split fieldwindings 96 of each motor 9i will be energized,- windings 91 remainingde-energized. The field current will flow through relay coils 99,closing relay switches I94 and thereby closing the armature circuits ofthe motors. Motors 9i will therefore be driven in one direction. Ifcontact 95 of switch 92 is closed, field windings 96 of each motor willbe open-circuited and windings 91 energized. Since the current throughwindings 91 also passes through relays 99, armature switches I04 will beclosed, and the motors will run in the opposite direction.

While it will be apparent that the preferred embodiments of theinvention'herein disclosed are well calculated to fulfill the objectsabove stated, it will be appreciated that the invention is susceptibleto modification, variation and change without departing from the properscope or fair meaning of the subjoined claims.

What is claimed is:

l. A screw type actuator including a gear housing, means for pivotallysecuring said gear housing on a stationary support, a screw shaftrotatably supported at one end by said housing,

means holding said screw shaft against axial movement with respect tosaid housing, means for driving said shaft, a ball nut mounted on saidshaft, means for limiting the travel of said ball nut in eitherdirection, a'thrust member carried by said ball nut for connection to adevice to be actuated, and means interconnecting said ball nut and saidthrust member and providing a limited frictional torque connectiontherebetween, engagement of the ball nut with either of its limitingstops creating sufficient torque to overcome said interconnecting means,whereby said ball nut will rotate against friction with respect to saidthrust member.

2. A screw type actuator including a gear housing, means for pivotallysecuring said gear housing on a stationary support, a screw shaftrotatably supported at one end by said housing, means holding said screwshaft against axial movement with respect to said housing, a worm gearfixed to said shaft, a worm supported by said housing and meshing withsaid worm gear, means for driving said worm, a ball nut mounted on saidshaft, means for limiting the travel of said ball nut in eitherdirection, a thrust member carried by said ball nut for connection to adevice to be actuated, and means interconnecting said ball nut and saidthrust member and providing a limited frictional torque connectiontherebetween, engagement of the ball nut with either of its limitingstops creating sufiicient torque to overcome said interconnecting means,whereby said ball nut will rotate against friction with respect to saidthrust member.

3. A screw type actuator comprising a housing, means for rockablysupporting said housing, a screw shaft rotatably held at one end by saidhousing and extending outwardly therefrom, means preventing said axialmovement of said screw shaft with respect to said housing, a gear fixedto said shaft within said housing, means for driving said gear, a ballnut mounted on said shaft, stop means carried by said shaft at eitherend thereof and engageable by said ball nut to limit the travel thereof,a thrust tube carried by said ball nut co-axially with said shaft, meansfor connecting the outer end of said thrust tube to a member to beactuated, said connecting means holding said thrust tube againstrotation, and frictional connecting means between said ball nut andsaidthrust tube and permitting relative rotation therebetween againstfriction when a predetermined torque is developed on said ball nut,engagement of said ball nut with either of said limiting stops servingto develop said predetermined torque.

4. An actuator for automotive toplifts or the like, including a housing,means for rockably supporting said housing on a stationary support, ascrew shaft rotatably supported at one end by said housing, meansholding said screw shaft against axial movement with respect to saidhous ing, a worm gear fixed to said screw shaft, a worm meshing withsaid worm gear within said housing, an electric motor operativelyconnectedto said worm, a ball nut movable on said screw shaft, limitstop members carried by opposite ends of said screw shaft, said ball nutbeing engageable with said stop members to thereby limit the travelthereof, a thrust tube connected at one end to said ball nut, means forconnecting the outer end 'of said thrust tube to a toplift linkage orthe like and for holding said thrust tube against rotation relative tosaid linkage, and frictional means connecting said thrust tube and ballnut, said frictional means being responsive to a predetermined torque topermit relative rotation against friction of said ball nut and saidthrust tube, engagement of said ball nut with either of said limitingstops serving to develop said predetermined torque, whereby said ballnut will rotate together with said screw shaft.

5. The combination according to claim 4, the tooth dimensions of saidworm and worm gear being such as to permit reversible operation, wherebyaxial force exerted on said thrust tube will move said ball nut alongsaid screw shaft.

6. The combination according to claim 5, said motor being supported bysaid housing for rocking movement therewith, and an anti-friction thrustbearing within said housing at one end of said Worm.

7. The combination according to claim 4, said screw shaft having anextension within said housing, an anti-friction bearing supporting saidextension at one end thereof, and a housing guide portion for the otherend of said extension, said worm gear being fixed to said extensionbetween said bearing and said guide portion.

8. In an actuator for toplift linkages or the like, a housing, means forsupporting said housing for rocking movement on a stationary support, ascrew shaft rotatably supported at one end by said housing and extendingoutwardly therefrom, means preventing axial movement of said screw shaftwith respect to said housing, a nut traveling on said screw shaft, stopmeans carried by the opposite ends of said screw shaft and engageable bysaid nut at the limits of its travel, a thrust tube connectable at oneend to said toplift linkage, frictional means comprising an annular keyconnecting the other end of said thrust tube and said nut, and a guideextension disposed within said other end of the thrust tube, said guideextension having an inner shoulder at one end thereof engageable withthe stop at the outer end of said screw shaft, the friction created bysuch engagement causing said nut to rotate relative to said thrust tube.

9. A screw type actuator including a gear housing, means for pivotallysecuring said gear housing on a. stationary support, a screw shaftrotatably supported at one end by said housing, means holding said screwshaft against axial movement with respect to said housing, means fordriving said shaft, a nut mounted on said shaft, means for limiting thetravel of said nut in either direction, a thrust member carried by saidnut forconnection to a device to be actuated, and means interconnectingsaid nut and said thrust member and providing a limited frictionaltorque connection therebetween, engagement of the nut with either of itslimiting stops creating sufficient torque to overcome saidinterconnecting means, whereby said nut will rotate against frictionwith respect to said thrust member.

10. A screw type actuator including a gear housing, means for pivotallysecuring said gear housing on a stationary support, a screw shaftrotatably supported at one end by said housing, means holding said screwshaft against axial movement with respect to said housing, a worm gearfixed to said shaft, a worm supported by said housing and meshing withsaid worm gear, means for driving said worm, a nut mounted on saidshaft, means for limiting the travel of said nut in either direction, athrust member carried by said nut'for connection to a device to beactuated, and means interconnecting said nut and said thrust member andproviding a limited frictional torque connection therebetween,engagement of the nut with either of its limiting stops creatingsufficient torque to overcome said interconnecting means, whereby saidnut will rotate against friction with respect to said thrust member.

11. A screw type actuator comprising a housing, means for rockablysupporting said housing, a screw shaft rotatabiy held at one end by saidhousing and extending outwardly. therefrom, means preventing axialmovement of said screw shaft with respect to said housing, a gear fixedto said shaft within said housing, means for driving said gear, a nutmounted on said shaft, stop means carried by said shaft at either endthereof and engageable by said nut to limit the travel thereof, a thrusttube carried by said nut c0.- axially with said shaft, means forconnecting the outer end of said thrust tube to a member to be actuated,said connecting means holding said thrust tube against rotation, andfrictional con necting means between said nut and said thrust tube andpermitting relative rotation therebeween against friction when apredetermined torque is developed on said nut, engagement of said nutwith either of said limiting stops serving to develop said predeterminedtorque.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 2,329,802 Westrope Sept. 21, 1943 2,424,492 Morris m July 22,1947

